The present invention relates to a method of manufacturing electric storage batteries and to an apparatus for manufacturing such batteries and is particularly, though not exclusively concerned with such batteries of lead acid type. The invention is concerned with recombinant batteries which are those which contain substantially no free unabsorbed electrolyte and in which the gases evolved during charging or operation are induced to recombine within the battery and are not vented to the atmosphere.
In conventional batteries which contain free electrolyte the intercell connectors generally pass through or over the intercell partitions and are sealed to them and the partitions in turn are sealed to the battery lid. This prevents electrolyte passing from cell to cell and thus eliminates the risk of intercell ionic leakage currents which degrade the battery's performance and shorten its service life.
It has, however been found that, contrary to conventional teaching, in recombinant batteriess containing substantially no free unabsorbed electrolyte the intercell partitions do not need to be sealed to the battery lid in order to prevent the battery failing prematurely due to intercell ionic leakage currents. Such a construction, in which there is a common headspace beneath the lid which communicates with all the cells, is both simpler to manufacture and has the advantage that a single vent may be provided for all the cells rather than having to provide a separate vent for each cell.
It is however believed that with the passage of time the surface of the plate straps and intercell connectors of such batteries, which are of lead or lead alloy in lead acid batteries, will become somewhat corroded by the action of the electrolyte and that this surface will therefore become somewhat pitted and porous. This pitted surface will provide a wicking path for electrolyte by virtue of capillary effects, that is to say the electrolyte will pass up the plates and along the plate straps and intercell connectors, and will then constitute an electrolyte path for intercell ionic leakage.